The leading assignee in this dataset holds 605 of the 13,094 records in scope, and it is an electron-microscope instrument maker rather than a device manufacturer. The top five assignees combined account for 11.6% of all records, and the top ten reach 16.6%, which means the field is far from consolidated. Most of the remaining filings sit with a long tail of semiconductor makers, battery manufacturers and universities, so a full competitive picture requires looking well beyond the leading names.

Not on the evidence available. Complete-year filings dropped from 745 in 2021 to 665 in 2024, an 11% pullback, after peaking at 824 in 2023. Filing counts for 2025 and 2026 look much lower still, but that is expected: publication typically lags filing by around 18 months, so the most recent years are always undercounted at the time of measurement. The honest read is a modest cooling from a 2023 peak, not a technology in retreat.

H01M, covering batteries, cells and fuel cells, is the largest single IPC subclass at 15.9% of the 13,094 records in scope. H01L (semiconductor devices, 12.5%) and H01J (electron and discharge tubes, 11.9%) follow closely, with G01N (material analysis and testing), B01J (catalysis and chemical processes) and C01B (inorganic compounds) each above 10%. Because a single patent can carry several IPC codes, these percentages add up to more than 100% and should be read as overlapping technique combinations rather than a strict breakdown.